The most important project of Haydn research in the 20th century, the first complete critical edition
Joseph Haydn Werke
will be completed in 2014. It is compiled by the Joseph Haydn Institute at Cologne, which was founded in 1955 and stores a comprehensive collection of sources, reproductions and all the Haydn literature. Beyond the complete edition basic philological work remains to be done — and should be done at this research center: A new edition of Haydn’s letters and a new
replacing the outdated one by Hoboken.
The paper is meant to be an introduction to László Somfai’s lecture on the Béla Bartók Thematic Catalogue in progress to be published by G. Henle Verlag. The author calls attention to a wealth of new thematic catalogues in print. The mutual interdependence of thematic catalogues and complete edition projects is emphasized. While discussing online databases on composers and thematic catalogues, the advantages and limitations of online resources are also pointed out.